Energy Recovery Ventilator Energy recovery ventilators (ERVs) capture much of the heat and humidity from stale indoor exhaust air and transfer it to the incoming ventilation air during the winter. During the summer, they transfer heat and moisture from the makeup air to the exhaust air to keep the house cooler and drier while supplying air changes.The use of desiccant systems for humidity conditioning sets ERVs apart from the simpler heat recovery ventilators (HRVs), which transfer heat only. The UltimateAir RecoupAerator 200DX energy recovery ventilation system from Stirling Technology, Incorporated, couples up to 96% heat recovery with exceptional operating efficiency. While the efficiency of conventional permanent split capacitor (PSC) motors drops quickly when running at less than 100% of the rated speed, the brushless DC variable-speed electronically commutated permanent-magnet (ECPM) motor in the 200DX provides almost vanishing power consumption at low speeds. It uses only 34 watts at 70 CFM and 200 watts at 210 CFM. Its low-speed operating efficiency is an industry benchmark— a particularly important advance, as these ventilation products often run nonstop, usually at low speeds.The Electricity Use Index (EUI) is a measure of watts used per CFM ...